Mefloquine Rifampicin

The use of proguanil plus atovaquone has been reviewed (14). Neuropsychiatric adverse events were more frequent with mefloquine, whereas other adverse events occurred with similar frequencies as with chloroquine plus proguanil and mefloquine. Proguanil plus atovaquone is contraindicated in severe renal insufficiency. Co-administration of proguanil plus atovaquone with rifampicin is not recommended because of reductions in plasma atovaquone concentrations. 

Rifampicin significantly reduces the plasma concentrations of mefloquine. Untii more is known, it may be prudent to avoid the combination. 

Rifampicin 600 mg daily was given to 7 healthy subjects for 7 days with a single 500-mg dose of mefloquine on day 7. The maximum plasma level of mefloquine decreased by 19% and the AUC decreased by 68%. Ri-fampiein, a potent enzyme-inducer, inereases the metabolism of mefloquine by the cytochrome P450 isoenzyme CYP3A4 in the liver and gut wall. The clinical relevance of this reduetion in mefloquine levels uncertain, but the authors suggest that simultaneous use of rifampicin and mefloquine should be avoided to prevent treatment failure and the risk of Plasmodium falciparum resistance to mefloquine. Until more is known, this would seem a sensible precaution. 

Ridtitid W, Wongnawa M, Mahatthanatrakul W, Chaipol P, Sunbhanich M Effect of rifampicin on plasma concentrations of mefloquine in healthy o[ a e.et. JPharm Pharmacol (2000) 52,1265-9,... 

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